This invention relates to an apparatus for forming domed bottoms in metallic one-piece can bodies which may, for example, be used as beer or beverage containers, and more particularly, to a floating apparatus for forming domed bottoms in one-piece can bodies which may yield radially to a misaligned can body or punch tool.
Many one-piece beer and beverage can bodies are formed with a beveled edge along the periphery of the bottom wall to increase the strength of the wall and thereby permit a minimum gauge metal to be used and thereby reduce the cost of the metal feed stock. There is, however, a tendency for the beveled edge to wrinkle or deform during the bottom doming step. Therefore doming apparatus frequently includes a pressure ring slidably disposed coaxially of the doming die to yield to the advance of the beveled border of the bottom wall of the can as the can body advances and the dome is formed within the bottom wall of the can body. Examples of apparatus for forming domes in the bottom walls of can bodies having a beveled border and incorporating both a doming die and a surrounding axially movable pressure ring are disclosed in the following U.S. Pat. Nos:
3,771,345 --Paramonoff--Nov. 13, 1973 PA0 4,289,014 --Maeder et al--Sep. 15, 1981 PA0 4,372,143 --Elert et al--Feb. 8, 1983
None of the above patents disclose doming dies or pressure rings which can radially float, much less such doming apparatus for accommodating misaligned tools or can bodies.
The Maeder U.S. Pat. No. 4,179,909 issued Dec. 25, 1979, discloses a domer assembly for forming domes in one-piece can bodies in which a doming die is mounted to float relative to the housing. However, this Maeder patent does not include a pressure ring axially mounted upon the doming die. Furthermore, the spring members utilized for yielding to radial pressures upon the doming die and for restoring the doming die to its central position after the radial pressure ceases are under constant tension and not provided with any positive abutment means for centrally locating the doming die after the radial pressures have ceased.
The Schaffer U.S. Pat. No. 4,109,502 issued Aug. 29, 1978, and owned by the Assignee of this application, discloses a segmented ring encompassed by a plurality of garter springs to resiliently mount floating ironing and drawing dies for one-piece can making apparatus.